In the case where an accident occurs in a distribution system for providing electric power from a substation to customers, a power failure occurs in an area where the electric power is supplied by that distribution system. In this case, it is required to promptly identify a section in which the power failure has occurred and restore the electric power supply.
FIG. 11 is a diagram schematically showing one distribution system.
As shown in FIG. 11, switches normally exist on the distribution system, and it is possible, by opening and closing a desired switch, to pass and stop electricity from upstream to downstream of the switch on the distribution system. As regards the switches, there are automatic switches capable of automatically or remotely controlling opening and closing thereof and manual switches for manually and directly controlling the opening and closing thereof.
FIG. 12 is an example of a high voltage distribution system diagram.
As shown in FIG. 12, the distribution system diagram is comprised of nodes (points) and spans for connecting them. Here, the node corresponds to the substation (node at a starting point of the system), switch and an electric pole in an actual distribution system. And the span corresponds to a distribution power line (high-voltage wire in the example in FIG. 12). Each node has absolute coordinates (geographic coordinates such as latitude, longitude and plane rectangular coordinates set on a drawing) set thereto, and each span can be identified by the absolute coordinates of the nodes on both ends. Such a distribution system diagram can be rendered by using a GIS (Geographical Information System) which is a system used to combine map data (electronic map) with other data and software (databases and the like) and comprehensively manage and process it or visually display it and analyze and determine it so as to display it on a display device or print it out.
In the high voltage distribution system diagram in FIG. 12, the distribution system described shown by a solid line represents one system, and the distribution system shown by a dotted line means a different system from that with the solid line. As shown in FIG. 12, a predetermined distribution system is appropriately connected to other distribution systems so as to accommodate one another with the electric power to be supplied to the customers. For that reason, it is possible, in the case where the electric power can no longer be supplied to predetermined customers in the predetermined distribution system due to an accident, an overload, a construction and so on a distribution line, to recover from the power failure in that area if the electric power can be supplied to the customers from another distribution system.
To be more precise, in the case where a predetermined distribution power line is cut off for instance, it is not possible as-is to supply the electric power to any customer downstream from a cut-off point. However, it is feasible to open the switches on both ends (upstream and downstream) of the cut-off point, stop the electricity, close the switches connected to the other distribution systems and pass an electric current to a downstream side of the cut-off point so as to immediately restore it except between the open switches and narrow the area in which the power failure is occurring. And it can be returned to the original distribution system after restoring the cut-off point.
Therefore, in the case where an accident occurs to the distribution system, it is important to promptly determine which switch should be operated to allow supply of the electric power to which area. For this determination, it is necessary to specify two nodes in the distribution system diagram and identify a span network which is a section comprised of the span between them.
Conventionally, to meet this demand, the distribution system diagram described on paper together with a map is checked by a person to identify the span network between the predetermined nodes.
As described above, there are the automatic switches capable of remote operation. And there is conventionally a system for switching the distribution system to control the electric power supply to the distribution system by operating the automatic switch for example as shown in Japanese Published Unexamined Patent Application 8-69490. If which switch should be operated to allow supply of the electric power to which area in the distribution system is known, it is possible, even when an accident occurs, to use this conventional system and isolate an accident occurrence point from the distribution system by the remote operation so as to switch the distribution system and supply the electric power from another distribution system to the areas further downstream from the accident occurrence point.
As described above, to promptly recover from a power failure due to an accident in a distribution system and so on, there is a conventionally adopted technique of accommodating with electric power from another distribution system and narrowing an area in which the power failure is occurring. And it is necessary, for the sake of switching the distribution system, to identify a desired section (a span network between two nodes) on a distribution system diagram.
Conventionally, however, this operation is manually performed so that it is not efficient.
Even in the case of a conventional control system for switching the distribution system by controlling an automatic switch, it is necessary, before switching the distribution system, to grasp which switch should be operated to allow supply of the electric power to which area. And thus, the operation for identifying the section on the distribution system diagram is also required. In the case of an accident in the distribution system, it is also necessary to monitor which area the electric power has been supplied to on the distribution system diagram by the switching of the distribution system performed to narrow the area in which the power failure is occurring before eventually eliminating a cause of the accident.
Furthermore, the automatic switches and manual switches for manually and directly controlling opening and closing are usually mixed on the distribution system. Therefore, the area capable of controlling the supply of the electric power is limited in the case of operating only the automatic switches (the supply of the electric power can be controlled only for a large area, for instance). For that reason, it is necessary to operate the manual switches as well as the automatic switches in order to carefully control the supply of the electric power and minimize the area in which the power failure occurs on the switching of the distribution system and restoration after the accident. To operate the manual switches, a worker must go to the site to perform the operation. Therefore, to promptly perform the operation, it is desirable to be able to simulate and monitor which switch should be operated to supply the electric power to which area or to interrupt the supply thereof to which area on the distribution system diagram.
Thus, an object of the present invention is to provide a system for simulating, in the distribution system, which switch should be operated to supply the electric power to which area or to interrupt the supply thereof to which area on the distribution system diagram.
The present invention is applicable as-is not only to the distribution system for the supply of the electric power but also to various other system diagrams such as piping of gas and water service. Thus, another object of the present invention is to provide a system for specifying arbitrary nodes for a predetermined system diagram and identifying the span network between them and a method thereof.